This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
During operation of a wireless communication system when transmitting data it is necessary to decode various channel codes that are used for forward error correction. These protect the transmitted signal from interference and also eliminate interference-induced errors in the signal.
One widely used encoding method is convolutional coding. In the convolutional coding the signal to be transmitted, consisting of symbols, is encoded into code words which are based on the convolution of the original signal with code polynomials. The convolutional code is determined by the coding rate and the coding polynomials. The coding rate (k/n) refers to the number (n) of produced coded symbols in relation to the number (k) of symbols to be coded.
An encoding method further developed from the convolutional code is a parallel concatenated convolutional code PCCC, which is also known as a turbo code. A PCCC may be generated from two recursive systematic convolutional encoders and an interleaver. The convolutional encoders can be identical or different. The resulting code includes a systematic part which corresponds directly to the symbols at the encoder input and two parity components which are the outputs of the parallel convolutional encoders. Typical channel codes, such as those used in 3G systems and WiMAX, are turbo codes, duo-turbo codes, and low density parity check (LDPC) codes. Various different wireless communication systems employ decoders and interleavers (sometimes termed de-interleavers) for the decoding of channel codes. The relevant decoders are often disposed within modems (modulator/demodulator), though in some embodiments they may be a hardware component separate from the modem itself. As throughput increases, there is a need to provide for faster decoding.